1. Field of the Invention
The present invention relates generally to a method for continuously processing a continuous textile fabric. More specifically, the present invention relates to an improved continuous processing method adapted to process a continuously connected textile fabric while moving it alternately forwardly and backwardly in such a manner that the forward traveling amount is greater than the backward traveling amount.
2. Description of the Prior Art
A continuous processing apparatus has already been put into practical use which is adapted to process a successively connected continuous textile fabric while moving the same alternately forwardly and backwardly in such a manner that the forward traveling amount is greater than the backward traveling amount. In this context, the words "successively connected continuous textile fabric" include woven fabrics, knitted fabrics and the like. In such a continuous processing apparatus, a successively connected continuous textile fabric is fed in a rope-like form and subjected to washing, scouring, bleaching, milling or similar treatment in the processing section in the path of travel of the fabric.
A continuous processing apparatus of interest is disclosed in U.S. Pat. No. 3,848,438, issued Nov. 19, 1974 to Yoshishige Tachibana et al, and assigned to the same assignee as the present invention. The referenced patent takes advantage of the fact that a seam is normally provided, at predetermined intervals, on the continuously connected textile fabric, and thus the seam presents a thickened portion as compared with the other portions of the fabric. Upon passing of the textile fabric between the squeezing rolls and through the processing chamber, the detectable portions such as the thickened seams are detected to control the feeding operation of each portion. The slacking amount of the textile fabric in the processing chamber is controlled by, at least, controlling the reciprocal feeding operation of the detectable portion in a given relation. To that end, the apparatus of the referenced patent includes a plurality of squeezing rolls and a textile feeding path comprising a plurality of processing liquid tanks arrayed in turn, and seam detecting limit switches are provided at the places of the squeezing rolls, with the distance of the path between adjacent limit switches being chosen to be almost the same as the interval of said seams. In a state where the seams are positioned at the squeezing rolls, and thus at the limit switches, all the squeezing rolls are driven in a forward direction at once and after a predetermined relatively large forward traveling amount, they are driven in a backward direction by a predetermined relatively small backward traveling amount, the difference between the forward and backward traveling amounts being chosen to be approximately equivalent to a distance of the interval of said seams divided by an integer. During the final backward driving operation in one full cycle of the forward and backward reciprocating operations for the number of times of said integer, said limit switches are enabled and according to the order of arrival the seams drive the limit switches to bring the squeezing rolls to a stop. When all the squeezing rolls are brought to a stop, the limit switches are disabled to repeat again said operation cycle. The referenced patent apparatus is disadvantageous in that in order to achieve improved processing results a number of tanks are required; this is not economical and also requires a large space for installation.
Another continuous processing apparatus of interest is disclosed in the copending United States patent application, Ser. No. 674,070, filed by the same inventor as that of the present invention and assigned to the same assignee as the present invention. The processing apparatus disclosed in the referenced application comprises a processing chamber containing a processing liquid, a squeeze roll assembly disposed above the processing chamber and guide rolls disposed on opposite sides of the squeeze roll assembly, the textile fabric in a rope-like form being introduced into the processing chamber at one end thereof and successively and spirally set toward the other end of the processing chamber so as to extend around the squeeze roll assembly and guide rolls and through the processing liquid many times and to travel as the squeeze roll assembly and guide rolls are rotated. The squeeze roll assembly and guide rolls are adapted to be reversibly rotatable and controlled so that the forward traveling amount of the rope-like textile fabric is greater than the backward traveling amount thereof. Thus, the rope-like textile fabric is subjected to impregnation with processing liquid and subsequent squeezing action many times while repeating alternate forward and backward travels, and it is gradually advanced an amount corresponding to the difference between the forward and backward traveling amounts for each reciprocating cycle.
In such a processing apparatus as disclosed in the referenced application, a slip could occur at successive nipped regions of the textile fabric set around the squeeze roll assembly. Since the amount of slip is different from nip to nip, an unevenness in the amount of travel of the textile fabric is caused at the individual nipped regions thereof during the processing which may take place for many hours, and hence an unevenness is caused in the length of successive portions of the textile fabric included between adjacent nips of the squeeze roll assembly. Extreme variations in the length of portions of the fabric included between adjacent nips, i.e. the individual loop lengths of the fabric, could cause kinking and twining around the squeeze roll assembly and breakage rakes of the textile fabric, and hence damage to and deterioration of the fabric. Thus, it is necessary to correct the individual loop length before such extreme variations in the individual loop lengths of the fabric occur.
In the past correction of the individual loop lengths was carried out by an operator through visual observation, which made accurate correction impossible. On the other hand, the processing liquid in the processing chamber becomes turbid and full of foam during the prolonged processing of the fabric, and this makes the correcting operation difficult and results in degradation of the fabric and stoppage of the apparatus for a long time period. In addition, the correcting operation requires the work of pulling a wet and weighty fabric, which is hard labor and must be done in a bad environment.
Therefore, the referenced patent application also proposes an apparatus for automatically and accurately correcting the individual loop lengths of the fabric in a continuous processing apparatus comprising a processing chamber containing a processing liquid, a squeeze roll assembly disposed above the processing chamber, and guide rolls disposed on opposite sides of the squeeze roll assembly, the textile fabric in rope-like form being introduced into the processing chamber at one end thereof and successively and spirally set toward the other end of the processing chamber so as to extend around the squeeze roll assembly and guide rolls and through the processing liquid many times and to travel as the squeeze roll assembly and guide rolls are rotated. More specifically, the method for correcting the individual loop lengths of the fabric disclosed in the referenced patent application comprises the steps of feeding a continuous textile fabric in a rope-like form set successively and spirally around a squeeze roll assembly disposed above a processing chamber so as to travel through the processing chamber, stopping the machine after a predetermined feeding time period or a predetermined number of reciprocating feeding times, severing the continuous textile fabric both at the input and output ends of the processing chamber, connecting a loop length correcting textile fabric having detectable portions spaced apart a predetermined distance therebetween commensurate with an ideal individual loop length to both ends of the textile fabric remaining in the processing chamber so as to form a large endless loop, feeding the said large endless loop through the processing chamber for correcting the individual loop lengths of the fabric upon detection of the detectable portions, removing the said loop length correcting textile fabric by severing at both ends thereof, connecting again a continuous textile fabric to be processed to the input and output ends of the textile fabric, as corrected, of the individual loop lengths remaining in the processing chamber, and again feeding the textile fabric for normal processing.
The apparatus disclosed in the referenced patent application can correct automatically and accurately the individual loop lengths of the continuous textile fabric. Nevertheless, the apparatus and method of the referenced patent application require that, in order to correct the individual loop lengths of the textile fabric in the processing chamber, the continuous textile fabric is once severed at the input and output ends of the processing chamber and, after correction of the individual loop lengths, the textile fabric is brought to the original position, the loop length correcting textile fabric is removed, and thereafter the textile fabric to be processed is connected again to the textile fabric remaining in the processing chamber. Repetitive separation and connection of the textile fabric to be processed and the loop length correcting textile fabric require repetitive manual operations, which productivity and make full automation of the process difficult to achieve.